Acids concept creation

Studying aspects of chemistry often includes grouping together some chemical materials with. similarities of behaviour. This is what we mean by concept creation. The concept of acidity is one of these. In chemistry teaching at this stage, teachers do not normally use the acids directly, but make use of their aqueous solutions. Studying. similarities of acidic behaviour means that we must include examples of non-acids to be sure that the learners can recognise the difference between the observed behaviour and materials that do not behave in this way. The two reactions chosen are ... 

So far, the emphasis has been on concept creation, roughly following the route of history. This brings us to around the eighteenth century. French chemist Nicolas Lemery (1645-1715) was born in Rouen and was one of the first scientists to develop theories on acid-base chemistry. By a theory, I mean a causal explanation that makes sense of all, or as much as possible, of the data that has been collected to date. The theory should be able to predict new information that can be collected and tested for compatibility. Earlier in this chapter I called this fertility . A theory of acidity should ej lain why all the members of the class of acids behave as they do and why the nonmembers do not. When chemists construct a theory, they may find that minor alterations are required. This is called accommodation and is felt to be natural in the development of a theory. If, however, there comes a point where accommodation cannot explain a large portion of the new evidence, a new explanation is created. This is called a paradigm shift and the topic of acidity offers examples of it that will be explored later. 

The mechanisms and reasons of catalytic activity of polyaniline (PANI)-type conducting polymers toward oxygen reduction in acidic and saline solutions are investigated by electrochemical and quantum-chemical methods. The PANI/thermally expanded graphite compositions were developed for realization of fully functional air gas-diffusion electrodes. Principally new concept for creation of rechargeable metal-air batteries with such type of catalysts is proposed. The mockups of primary and rechargeable metal-air batteries with new type of polymer composite catalysts were developed and tested. 

The critical load concept is intended to achieve the maximum economic benefit from the reduction of pollutant emissions since it takes into account the estimates of differing sensitivity of various ecosystems to acid deposition. Thus, this concept is considered to be an alternative to the more expensive BAT (Best Available Technologies) concept (Posch et al., 1996). Critical load calculations and mapping allow the creation of ecological-economic optimization models with a corresponding assessment of minimum financial investments for achieving maximum environmental protection. 

Terminal groups can be inserted on the surface of NPs with a procedure called functionalization , in order to increase their dispersability and their biocompatibility [181, 185], The creation of free carboxylic acid and amino acid moieties on the surface are the most commonly used functionalization procedure for enzyme immobilization and stabilization [181, 185], In the same concept, Jiang and his coworkers functionalized silica coated-NPs with imidazolium-based ionic liquids [179]. The immobilization of ionic liquid facilitates the reuse of these solvents, while it provides a microenvironment in which the enzyme exhibits high activity and stability. 

Fig. 25 Concept of the creation of supramolocular dye architectures showing polymorphism . Structure of the designed dipolar dye with pyridine and carboxylic acid terminals. Reprinted with permission from [141]...

The necessity for the creation of the concept of a variable E2 process arises because of the number of possible variations that can intrude in the overall ehmina-tion process. For example, it is well appreciated that some bases B will be stronger than others or (in other words) some alkyl halides will be more acidic toward those bases than others. 

A closely allied concept is that of DNA-templated organic synthesis (DTS) [26-28], It is based on the translation of nucleic acid sequences into corresponding synthetic compounds, and is primarily used in the creation of libraries of DNA sequence-programmed small molecules. DTS does not require adjacent functional groups to proceed efficiently [29], can mediate sequence-programmed multistep syntheses of small molecules [30], and can enable reaction pathways that are impossible to achieve by conventional synthetic strategies [31], This principle was shown to be particularly valuable in the selection of a Uhraiy of macrocyclic compounds [32]. 

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